Overclocking means cores always run high?

Generally when the full speed is not required it will throttle down if you did not disable that option in the bios. However, it will not use a true speedstep that has multiple levels. I will either be in the throttled down state, which for my 2500K is about ~1.6GHz or full blast which is 4.8GHz with nothing inbetween like under normal circumstances.

EDIT: Download cpu-z and it will show you what speed your CPU is running at and it will update on the fly as the speed changes wile you are idle as opposed to running something that requires more processing power.

what option is this?

all the guides i'm reading say to disable all those power saving features
eg.
Limit CPUID Maximum, C1E Support, OverSpeed Protection, etc

What should i do?
I'm not looking to overclock more than 4.3 - 4.5.

Speedstep or possibly EIST in the BIOS as well as C1E (halt state) will control things such as throttling the CPU.